Load Check

I just got some precision delta 124gr JHPs to try out but only have WSF on hand.

I have been reloading 124gr montana gold FMJs with 4.8gr WSF at 1.140" with great success and am at the low end of the recommended loads per my manuals. What I don't have is any JHP data for 124, plenty for 147 and 115 and other powders for 124 but not WSF.

Based on the length of the bullets with my calipers the OAL of the JHPs is 0.0115" shorter than the FMJs.

I should be safe starting at the same load data from the JHP correct? Basically I wold be loading with 0.0115" more case volume for the same charge weight? Just want a quick second check before loading a few up.

I agree given the same oal of 1.140" you should be ok. But when changing shapes of bullets it is still a good practice to start at the starting load which in your case would be 4.7gr for a fmj according to Hodgdon's.

You also should load up a dummy round with the JHP bullet at 1.140" and make sure it will seat in your chamber before you start your load. The shape of the hp may prevent you using it at that length. If that is the case and you have to reduce your OAL of the hp to chamber in your gun. Then I would definitly reduce your charge as well.

I have tested some dummies in my 2 primary guns and they both feed well from the magazine. Most of the data I have seen recommends more powder for JHP so starting at the low end of FMJ data should be perfect.

I am going to load up a few tonight and give them a go tomorrow, I will let you know how they turn out.

Hodgdon lists 1115fps at their max load for their FMJ data, but does not list anything for JHP.

What are your thoughts on this load? Am I over pressure by looking at the velocities? I am going to back the overall length out 0.01" to 1.145-1.150" and see how that goes. I checked feeding some dummy rounds from a magazine in a few of my guns and they chamber and feed fine on the bench. Also no signs of high pressure from the primer on the 10 that were tested.

That is why it is always a good idea to work your load up from lower charges to higher checking velocities as you go. You can identify gradual increases in speed to similar increases in charge weights. Also you can spot where velocities may spike or flatten out on increases, which would probably indicate a near max charge.

increaseing your OAL can't hurt as long as it chambers fine and will lower the pressure.

You also may be fine if no pressure signs are appearing. You can not expect to get the exact same velocity that is listed in the load manuals, every barrel is different. Some may give higher pressure others lower. Even the difference between your chronographs avg. and theirs will vary. It may just be the normal velocity with that load and your barrel. Many things affect velocity even temperature.

If you carefully note Hodgdon's reloading data, their velocity of 1115fps with the 124gr projectile is a FMJ loaded to a COL of 1.169. That is significantly longer, even given the bullet profile, of your JHP. This could also explain why their velocity maxed at 1115fps even with a higher powder charge.

As stated above, you should always work up your loads. With a chronograph, it is very easy to see when you are approaching a wall. The .1gr increment in charge that was giving 20-30fps increases in velocity suddenly only gives 15-20fps. That is where you stop. Back off a tenth or two and call it you max for the firearm you were testing the load in.

Thought I would be good at this charge weight with a large free space in the case going to JHP and being near the min charge weight. I will see how the longer OAL does since I have seen a lot of data from others using shorter OAL and same bullets with higher charge weights, and getting the same velocity as me.

I will see how the longer OAL does, but my primers look great, basically new with the exception of the firing pin dimple.

Thanks for the feedback. Glad I only loaded 10 of them instead of 100s